scholarly journals CLASSICAL AND QUANTUM FEATURES OF THE MIXMASTER SINGULARITY

2008 ◽  
Vol 23 (16n17) ◽  
pp. 2353-2503 ◽  
Author(s):  
GIOVANNI MONTANI ◽  
MARCO VALERIO BATTISTI ◽  
RICCARDO BENINI ◽  
GIOVANNI IMPONENTE
Keyword(s):  
Review Paper ◽  
Cosmological Singularity ◽  
Mixmaster Model ◽  
Classical Picture

This review paper is devoted to analyzing the main properties of the cosmological singularity associated with the homogeneous and inhomogeneous Mixmaster model. After the introduction of the main tools required to treat the cosmological issue, we review in detail the main results obtained over the last forty years on the Mixmaster topic. We first assess the classical picture of the homogeneous chaotic cosmologies and, after a presentation of the canonical method for the quantization, we develop the quantum Mixmaster behavior. Finally, we extend both the classical and the quantum features to the fully inhomogeneous case. Our survey analyzes the fundamental framework of the Mixmaster picture and completes it by accounting for recent and peculiar outstanding results.

scholarly journals COVARIANT FEATURE OF THE MIXMASTER MODEL INVARIANT MEASURE

2002 ◽  
Vol 11 (08) ◽  
pp. 1321-1330 ◽  
Author(s):  
GIOVANNI IMPONENTE ◽  
GIOVANNI MONTANI
Keyword(s):  
Invariant Measure ◽  
Arbitrary Function ◽  
Chaotic Behavior ◽  
Time Variable ◽  
Cosmological Singularity ◽  
Constant Of Motion ◽  
Set Up ◽  
Lapse Function ◽  
Mixmaster Model ◽  
Hamiltonian Analysis

We provide a Hamiltonian analysis of the Mixmaster Universe dynamics showing the covariant nature of its chaotic behavior with respect to any choice of time variable. Asymptotically to the cosmological singularity, we construct the appropriate invariant measure for the system (which relies on the appearance of an "energy-like" constant of motion) in such a way that its existence is independent of fixing the time gauge, i.e. the corresponding lapse function. The key point in our analysis consists of introducing generic Misner–Chitré-like variables containing an arbitrary function, whose specification allows us to set up the same statistical scheme in any time gauge.

scholarly journals A SCENARIO FOR THE DIMENSIONAL COMPACTIFICATION IN ELEVEN-DIMENSIONAL SPACE–TIME

2004 ◽  
Vol 13 (06) ◽  
pp. 1029-1036 ◽  
Author(s):  
GIOVANNI MONTANI
Keyword(s):  
Power Law ◽  
Dimensional Space ◽  
Conformal Factor ◽  
Space Time ◽  
Geometrical Theory ◽  
Cosmological Singularity ◽  
3 Dimensional ◽  
Dimensional Space Time ◽  
Mixmaster Model

We discuss the inhomogeneous multidimensional mixmaster model in view of the appearing, near the cosmological singularity, of a scenario for the dimensional compactification in correspondence to an 11-dimensional space–time. Our analysis candidates such a collapsing picture toward the singularity to describe the actual expanding 3-dimensional Universe and an associated collapsed 7-dimensional space. To this end, a conformal factor is determined in front of the 4-dimensional metric to remove the 4-curvature divergences and the resulting Universe expands with a power-law inflation. Thus we provide an additional peculiarity of the eleven space-time dimensions in view of implementing a geometrical theory of unification.

Statistics and parallaxes

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz
Keyword(s):  
Experimental Design ◽  
Statistical Methods ◽  
Review Paper ◽  
Systematic Errors ◽  
Past Experience ◽  
Random Errors ◽  
Trigonometric Parallaxes ◽  
Systematic And Random Errors

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.

Potential Uses of Vinegar as a Medicine and Related in vivo Mechanisms

2016 ◽  
Vol 86 (3-4) ◽  
pp. 127-151 ◽  
Author(s):  
Zeshan Ali ◽  
Zhenbin Wang ◽  
Rai Muhammad Amir ◽  
Shoaib Younas ◽  
Asif Wali ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Review Paper ◽  
Heart Diseases ◽  
Folk Medicine ◽  
Active Role ◽  
Current Review ◽  
Different Types ◽  
Positive Effect

While the use of vinegar to fi ght against infections and other crucial conditions dates back to Hippocrates, recent research has found that vinegar consumption has a positive effect on biomarkers for diabetes, cancer, and heart diseases. Different types of vinegar have been used in the world during different time periods. Vinegar is produced by a fermentation process. Foods with a high content of carbohydrates are a good source of vinegar. Review of the results of different studies performed on vinegar components reveals that the daily use of these components has a healthy impact on the physiological and chemical structure of the human body. During the era of Hippocrates, people used vinegar as a medicine to treat wounds, which means that vinegar is one of the ancient foods used as folk medicine. The purpose of the current review paper is to provide a detailed summary of the outcome of previous studies emphasizing the role of vinegar in treatment of different diseases both in acute and chronic conditions, its in vivo mechanism and the active role of different bacteria.

Non-Steroidal Anti-inflammatory Drugs (NSAIDs): Synthesis of Ibuprofen, Naproxen and Nabumetone

2019 ◽  
pp. 19-27
Keyword(s):  
Review Paper ◽  
Inflammatory Drugs ◽  
Anti Inflammatory ◽  
Synthetic Approaches

This review paper covers the major synthetic approaches attempted towards the synthesis of some Non-Steroidal Anti-Inflammatory Drugs (Naproxen, Ibuprofen and Nabumetone)

Sistem Kendali Kendaraan untuk Keselamatan Aktif: Review Paper

2017 ◽  
Vol 3 (1) ◽  
pp. 1-12
Author(s):  
Rina Ristiana ◽  
Arief Syaichu Rohman ◽  
Ary Setijadi Prihatmanto ◽  
Carmadi Machbub
Keyword(s):  
Review Paper ◽  
Low Level

Telah dilakukan telaah makalah mengenai sistem kendali untuk meningkatkan keselamatan berkendaraan. Sistem kendali ditentukan pada low level yang berfungsi untuk menjaga kestabilan kendaraan. Kendaraan dijelaskan dalam bentuk dinamika dan sistem pemindah daya. Permasalahan sistem kendali pada mobil listrik terletak pada ketersediaan energi baterai yang mempengaruhi kestabilan kendaraan, sehingga perlu optimisasi efisiensi energi.

A Review Paper on Human Computer Interaction

2018 ◽  
Vol 8 (4) ◽  
pp. 53 ◽  
Author(s):  
Himanshu Bansal ◽  
Rizwan Khan
Keyword(s):  
Human Computer Interaction ◽  
Computer Technology ◽  
Mental Model ◽  
Review Paper ◽  
Current Approach ◽  
Automated System ◽  
Age Group ◽  
Long Time ◽  
Interaction Research ◽  
Computer Interaction

The advancement in the development of computer technology has led to the idea of human computer interaction. Research experiments in human computer interaction involves the young age group of people that are educated and technically knowledgeable. This paper focuses on the mental model in Human Computer Interaction. There are various approaches of this review paper and one of them is highlighting current approach, results and the trends in the human computer interaction and the second approach is to find out the research that have been invented a long time before and are currently lagging behind. This paper also focuses on the emotional intelligence of a user to become more user like, fidelity prototyping. The development and design of an automated system that perform such task is still being accomplished.

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